ex_dict = {}

ex_dict = {'a': 1, 'b': 2, 'c': 3}

ex_dict['a']

ex_dict['a'] = 30
ex_dict['x'] = 30

9 in ex_dict
'a' in ex_dict
1 not in ex_dict

# 键值对：key:value

# len
len(ex_dict)
# del
del ex_dict['a']
del ex_dict
